The invention relates to a welded joint between plastic parts, such as are generally known in the plastic-processing industry for articles made of thermoplastics.
Where welded joints subjected to high loads are concerned, it is often desirable to check the strength of these. Mechanical processes for checking welded joints have a destructive effect, and in sampling which is approximately uniform in statistical terms this results in the destruction of many, sometimes very expensive workpieces.
An object of the invention, is to make a welded joint between plastic parts, in such a way that it can be checked for perfect welding quality reliably and in a non-destructive way.
According to the invention, this object is achieved by means of providing a coating of X-ray contrast medium with a sharp outline to one of the parts being welded. Because an X-ray contrast medium of sharp outer contour is introduced into the welding gap before the parts are joined together, it is possible, after the welded joint has been made, to ascertain whether the outer contour of the X-ray contrast medium has run within the welding material, this pointing to a good welding quality, or whether the edge contour of the coating of X-ray contrast medium is more or less sharply set-off, as before; in the latter case, this would point to poor running of the material within the welding gap and therefore to a poor welding quality.
Preferred embodiments of the invention use a film strip to carry the X-ray contrast medium. In certain preferred embodiments the film strip has saw tooth edge portions. The preferred embodiment use various X-ray contrast medium material to facilitate economical and efficient production techniques.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.